1. Field of the Invention
This invention relates to an apparatus and method for effectively automatically cutting a braid of a shielded wire having a relatively large diameter for use in an electric vehicle and others.
2. Description of the Related Art
Traditionally, a shielded wire was processed manually in all the steps.
Specifically, the sheath of the tip of a shielded wire cut into segments of a prescribed length is stripped using a tabletop tool so that the braid of conductive metal is exposed. The braid is cut into segments each having a prescribed length. With a shield contact of conductive metal manually inserted into the shielded wire, the braid is folded back toward the contact using a center punching. With a shield pipe of conductive metal manually inserted in the shielded wire and braid sandwiched between and kept in contact with the shield contact and the shield pipe, the shield pipe is squeezed using a squeezing machine. Further, the inner face at the tip of the shielded wire is stripped using the tabletop tool so that a terminal is connected to a core wire by a crimping machine (The shape and other details of the shield contact and shield pipe can be seen from FIG. 3).
The shielded wire is used in such a mode that a connecting flange is combined with the shield pipe and earth-connected to a vehicle body along the outer surface of the housing of resin. The terminal of the shielded wire is connected to a motor, inverter or battery of an electric vehicle.
However, in the above conventional means for cutting the braid of the shielded wire, the braid was manually cut using snips. Therefore, the length of each of the segments of the cut braid is uneven. The tip of cut braid is liable to be irregular. The quality is not stable, and a large number of man-hours is required. This presents a problem of increasing the production cost.
In view of the above problem, a first object of this invention is to provide an apparatus which can cut the braid of a shielded wire into precise lengths cleanly with no irregularity and effectively with a small number of man-hours.
A second object of this invention is to provide a method for cutting the braid of a shielded wire into precise lengths cleanly with no irregularity and effectively with a small number of man-hours.
In order to attain the above first object, in accordance with this invention, there is provided a braid cutting apparatus for a shielded wire comprising: a die located outside an exposed braid of the shielded wire; means for opening the braid; a punch which is to advance inside the braid; and a guide member for guiding the braid in a direction to open further and an inner sheath of the shielded wire inside the braid to an inside of the punch.
In this configuration, the exposed braid of the shielded wire is inserted into the inside of die, the braid is opened outwardly in taper by a braid opening means, the inner sheath of the shielded wire is inserted in the inside of the punch and the braid is further opened in taper outwardly by a guide member. For this reason, the tip of the punch is inserted surely and smoothly inside the braid, i.e. between the braid and the inner sheath of the shielded wire so that the braid can be surely sheared between the punch and the die.
In the above apparatus, preferably, the opening means comprises: a pair of opening pallets which are freely reclosable, a pair of sliding members with the pair of opening pallets fixed; a link for moving the pair of sliding members in opposite directions; and driving means for swinging the link.
In this configuration, the link is swung by the driving means so that the pair of sliders are opened or closed simultaneously with the opening pallets. Therefore, the braid of the shielded wire is pressed repeatedly by the opening pallets under appropriate force. Accordingly, the braid can be surely opened in a trumpet without being injured.
In the apparatus described above, preferably, the guide member is made dividable, and when the punch advances, the guide member is opened outwardly by the driving means and a moving means to retreat.
In this configuration, since the guide member opens and retreats, when it is opens, the braid is opened further outwardly. For this reason, the punch is inserted more surely inside the braid.
In order to attain the second object, there is provided a method of cutting a braid of a shielded wire comprising the steps of: opening an exposed braid of the shielded wire, further opening the braid along an outer slope of a guide member while guiding an inner sheath of the shielded wire inside the braid to an inside of a circular punch, and shearing the braid into a required length between the punch and a die located outside the braid while advancing the punch inside the braid.
In this configuration, the braid opened primarily opened by the opening means is guided along the outer slope of the guide member so that it is further (secondarily) opened greatly outwardly. The inner sheath of the shielded wire is smoothly inserted into the guide member, i.e. inside the punch along the inner slope of the guide member.
In the method described above, preferably, after the braid is opened along an outer slope of the guide member, the guide member is opened outwardly.
In this configuration, since the braid is opened further outwardly when the guide member is opened, the punch is inserted more surely inside the braid. Thus, the tip of the punch and that of the braid do not interfere with each other so that the braid does not bend inwardly. This prevents poor cutting of the braid.
The above and other objects and features of this invention will be more apparent from the following description taken in conjunction with the accompanying drawings.